UNEXPECTED SOFT UPDATE INCONSISTENCY; RUN fsck MANUALLY
koitsu at FreeBSD.org
Tue Sep 30 04:32:52 UTC 2008
On Tue, Sep 30, 2008 at 11:40:46AM +1000, Andrew Snow wrote:
> Matthew Dillon wrote:
>> It can take 6 hours to fsck a full 1TB HD. It can
>> take over a day to fsck larger setups. Putting in a few sleeps here
>> and there just makes the run time even longer and perpetuates the pain.
> We have a box with millions of files spread over 2TB, on a 16 disk RAID.
> Foreground fsck takes almost 8 hours, so background fsck, which takes
> almost 24 hours or more, is my only option when I want to bring the box
> back online quickly. And UFS Snapshots are so slow as to be completely
> I've now converted the volume to ZFS, and am now enjoying instant boot
> time and higher speed I/O under heavy load, at the expense of memory
>> My recommendation? Default UFS back to a synchronous fsck and stop
>> treating ZFS (your only real alternative) as being so ultra-alpha that
>> it shouldn't be used.
> Completely agree. ZFS is the way of the future for FreeBSD. In my
> latest testing, the memory problems are now under control, there is just
> stability problems with random lockups after days of heavy load unless I
> turn off ZIL. So its nearly there.
It just now occurred to me that this entire conversation should've been
moved to freebsd-fs weeks ago. *laugh* Oh well. :-)
You're the first person I've encountered who has had to disable the ZIL
to get stability in ZFS; ouch, that must hurt.
ZFS stability has been discussed on freebsd-fs numerous times, but the
answers provided are always penultimate; no one (AFAIK) has examined how
to solve this from the start (specifically new FreeBSD installations).
Yes, I know sysinstall/sade doesn't support ZFS (though the PC-BSD folks
have apparently implemented this), but that's not what I'm talking
about. I'm talking about the most commonly-encountered problem: kmem
exhaustion. People want to be able to install FreeBSD then say "Okay!
Time to give ZFS a try!" on some separate disks, and have it work. They
don't want to encounter kmem exhaustion half way through the migration
process; that's just going to dishearten them.
I'll be starting up a new topic on freebsd-fs later tonight with an idea
I came up with for solving this out-of-the-box. I have a feeling I'm
going to get told "so who's going to do all the work?" or downright
flamed, but I hope it induces a discussion of ideas, specifically with
regards to new FreeBSD installations.
| Jeremy Chadwick jdc at parodius.com |
| Parodius Networking http://www.parodius.com/ |
| UNIX Systems Administrator Mountain View, CA, USA |
| Making life hard for others since 1977. PGP: 4BD6C0CB |
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